


Not a Hero, Not a Villain (Undertale x My Hero Academia)

by BubblyShip



Category: Undertale (Video Game), 僕のヒーローアカデミア | Boku no Hero Academia | My Hero Academia
Genre: Cats, Crossover, Depression, F/F, F/M, Genocide Run, M/M, Mentions of Suicide, Other Additional Tags to Be Added, Teacher Sans (Undertale), Universe Travel, femalesans, girlsans, hinting at suicide, sans has a pet cat now, undertale x bnha
Language: English
Status: In-Progress
Published: 2021-02-26
Updated: 2021-03-06
Packaged: 2021-03-17 13:06:43
Rating: Not Rated
Warnings: Graphic Depictions Of Violence, Major Character Death
Chapters: 5
Words: 9,979
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29717607
Author URL: https://archiveofourown.org/users/BubblyShip/pseuds/BubblyShip
Summary: After a genocide run, when Frisk decided to destroy the world, Sans' soul didn't make it back. It ended up inside the body of a woman, who'd quirk was to destroy her soul and place another into her body.Now, in the body of a woman, with no money, no friends, and nothing but his natural skeleton powers.Until someone sees him and offers for him to become an assistant teacher in one of the most powerful schools in the world. It's an offer Sans can't refuse.
Relationships: Midoriya Izuku/Todoroki Shouto
Comments: 8
Kudos: 58





	1. Credit/Info

Undertale and My hero obviously belong to their rightful owners. I did draw the cover as well, so that'll probably be my design for human female Sans. 

And I will give credit to the people who actually inspired this fic and got me into My hero academia in the first place. I read three specific fics that made me want to watch the show and possibly write a crossover. (Undertale x bnha crossover), (Sapphire Judge, and (Bones) all on Wattpad. These aren't my favorite fics but I wasn't able to sleep one night, went onto recommended on the home page, and these three caught my eye. So this fic is inspired by them, though Sans isn't going to be a student, but instead an assistant teacher. So shoutout to those people for helping me get this idea.

This book isn't going to focus on Sans being a girl, instead it's going to just throw him into what happens in the anime and see how things change. I'm still watching it (I animate while it runs in the background) and right now I'm on season two, so try not to spoil anything in the comments, alright? But if you want a story that focuses on Sans experiencing life as a girl, then go check out Woman's Vision, since that goes more into detail about the changes of a male skeleton going into a human womans body. 

BUT: This is important, I should warn you guys that this isn't going to be like my other books. I'm writing this purely for fun. There isn't going to be any majorish plot, I can't guarantee I know where this will go since I'm still watching the anime, so this is purely for me to have some fun with and see how Sans develops interactions between his students and fellow teachers. So if this isn't finished, yeah it won't be. This won't have a consistent schedule for uploading, and I can't say it'll be looked over, either. I just wanted to have one fic where I an write whenever I have writers block on other stories. So don't ask for updates on this. I got a lot of stuff to do and I'm just throwing this out here because I know it'll probably never be seen if I don't. If you want better quality content, I have like 50 Undertale stories, I'm drowning dear lord please help me-

Okay yeah anyway I also have to ask ya guys a question. So far the only ship I really have planned for this is Tododeku, and I need a ship for Sans because apparently I cannot write an Undertale fic unless Sans is dating someone. I don't know who to ship him with, mostly because I haven't seen enough of the adult characters yet. No, I'm not shipping him with a student, since he's in his twenties in this fic. I was considering Tomura Shigaraki (who's apparently only 20? I thought he was like 25 so in here he's going to be 25). I have an idea for why they'd work together quirk wise, but so far since I've only seen him twice on screen I don't know much about him. Ya guys have any other suggestions that'd work better (that's a villian)? I'm still iffy on the Tomura Shigaraki decision because, again, I need more screentime with little handy boi. 

The first chapters going to be uploaded in like, 5 minutes, stay tuned guys.


	2. Prologue

It was the smell of shit he awoke to. Not bacon, not the usual spaghetti, no, shit. Literal shit. When dogs snuck into your house for bones, you knew that smell, and this was certainly it.

To say Sans was jumping out of bed refreshed was a lie. He was cranky, his back hurt, and overall, felt like the shit he was smelling. His new body, whatever he woke up inside of, was uncomfortable as hell.

Yeah, Sans wasn’t expecting to wake up in a human girls body, wearing nothing but a t-shirt and underwear, but honestly this was a better situation than what he left off at. Being murdered by Frisk constantly flashed across his mind, reminding him of what he just escaped from. So, being a human girl? He was hella down for that. Better than dying brutally.

It didn’t feel much different from being a skeleton. Just as if he was himself, just wearing high heels from his increased height and wearing a wig. Adjusting didn’t take too much time. At least, for his body.

Adjusting to his room, though, was.

Cars practically screamed down the street below as he pinched his new fleshy nose, stepping over a literal pile of cat shit as he made his way to the mirror. The new room he awoke inside of was a cramped one room apartment, with a broken window hanging by meer threads to the wall, broken and desolate. It was cramped, small, practically demolished from age and miscare. Papyrus would have had a flip or two if he saw it.

Sans watched a cat, skinny with it’s ribcage showing, vomit profusely onto the vanity Sans found himself standing in front of. He gave a soft look of sadness at the creatures state before he dragged his eyes up to look at himself.

And man, was he not looking any better.

His face was skinny, to the bone (literally), skin stretched out with hollowed, almost pitiful eyes. The clothes he wore clung so loosely that his body was more akin to a stick than a humans. This person, whoever owned this body before him, hadn’t eaten in days. His hair stuck out in white, unbrushed frills, with black eyes and white pupils staring back at him. Not naturally human. So he did retain his magic.

That’s why he picked up the cat and dragged his own skinny ass to the corner of the room, where a lone kitchen sat. if it could be called a kitchen. One single seat sat before an old table, wobbly, and all the few cabinets had was chipped bowls and ramen noodles. Without much choice, he made them using the broken microwave and sat the cat down, feeding her some canned tuna by the door as he looked down at the stacks of papers littered across the small table.

Some of them were bills. Lots of bills. The numbers easily reached hundreds of thousands. Medical insurance. Gambling losses. For a girl that looked like him - er, his body - only with blonde hair and blue eyes, and a more healthier look. Sans ate the crunchy noodles, going for fourths when he realized just how hungry this body truly was. The cat ate just as much, as if they hadn’t eaten in days.

The deeper he dug, though, the more Sans saw about this womans terrible life. She was a woman, in her twenties, whose future was destroyed by her Father when he gambled away their house. They lost everything when she was just a teen. When she became an adult, her future wasn’t bright because of low grades, and she succumbed to the gambling her Father did after he passed away, leaving behind only debt for his daughter. That only led to more loss. And that loss led to depression. No friends, no family, she started to loss hope. Didn’t feed herself. Couldn’t even leave bed.

He leaned back in his chair, sucking up the last noodle from his lower lip, and summarized all of the information he had. Girl got a bad Dad. Girl become broke. Girl become woman. Woman graduate. Her life shit. She dies in bed. Then Sans takes over.

But… why was her life this bad? Where were the relief programs? The help from the Government? Apparently she could have been given a ‘quirk’ loan, something that would have removed all of her debt if she applied her quirk to a Government run facility, like the army, schooling, or some special service, but her ‘quirk’ wasn’t one she could apply. As proven by a series of letters between her and the program itself.

‘ _We are sorry to inform you that your quirk does not qualify you to the Q.L.P, otherwise known as the Quirk Loan Program. While you do have a quirk, a soul one at that, you cannot provide relief or help in any special way that would help. You’re quirk allows for a onetime use, a soul transfusion, upon which your soul would be removed from your body and be set to peace. This cannot be placed in any of our several categories to qualify for this program.’_

So that was this girls quirk. She had the ability to set her soul into eternal peace. She must have also had the offhand ability of placing a new soul into her body when she did move, which caused Sans’ own adrift soul be to forced inside. That was the best explanation he could come up with, and it made enough sense.

A suicide, then. She had given up and used her quirk. A one time move.

Unintentionally, though, she had pawned off all of her debts onto Sans, so that wasn’t exactly thrilling. It wasn’t something new, Sans himself worked three jobs to pay the bills before, but he kinda thought of this like a fresh start. Now he knew he had to get a job in a new world, as a different person, with people who had things called quirks. Weren’t those just magical attacks?

Sans tried to focus on the positive as he found a collar for the cat and slipped it onto her, followed by a leash, and stepped outside of the apartment door. This was a new start, just with some baggage. And Sans did have his own powers, since those were directly connected to his soul, not his body. If the girl simply dragged his soul into her body, then he was the same content, just a different container. That meant he might be able to apply for the loan after all, if he pretended his powers were a quirk.

Compared to the shitstorm of a reset Sans faced before, this was easily much more hope inducing. Sans actually had something to work towards. No risk of all of his hard work being erased.

The only thing that really sucked was that Papyrus wouldn't be here, but he knew Chara themself wouldn't let his bro go unwatched. They always had a soft spot for him, and Sans knew they brought his soul back before anyone else's after Frisk killed him. And it wasn't like Sans got to spend much time with his brother anyway. Papyrus was always killed early.

Sans walked the girls cat, letting the little creature bounce on her paws as they walked down the street. Sans made a mental note of where the apartment - his apartment, since this was his life - was before he left. Tried not to dwell on what this could mean for his future. Because he wasn't Sans the skeleton anymore. He was… Whoever this girl was now.

Sans walked down the street, admiring the sun that eluded him for years as strange looking people passed him. This wasn't so bad. Heck, if Papyrus was here, it'd be almost perfect. Sans could finally be free of the resets.

He spent the first day just doing something he hasn't been able to do in a long time. Enjoying life. He ate French fries and shuffled along pathways, laying below the scenery. Glancing up and realizing this may just be his life now.

Sans could… he knew the resets had to come to an end one day. And he had come to terms with separating from him. Perhaps that's why he easily transferred from one life to another seamlessly. Because he's become so numb to it.

The day was nice. Not great. But nice. When dogs snuck into your house on the daily, you started to grow an appreciation for cats, so Sans didn't mind caring for the girls cat as he went about. Eventually the cat curled upon his lap purring, so he would say that was pretty successful with the day.

In the evening Sans was eating a hot dog, letting ketchup dribble out of his mouth and down his chin. He should get a job soon. He knew he was vulnerable to depression, so it'd be best to get a bounce in his schedule before he gave up like the girl did. And he knew she didn't intend for anyone to replace her, but fuck, that was a lot if debt he'd have to pay off. A good chunk should be gone after he applied for the quirk loan.

Just once he figured out how to.

It shouldn't be too hard. This world was a lot like the one's Papyrus liked to read about, one with super heros. They were deeply ingrained in this society, but Sans had his magic, so he should be fine. Should be.

That was until the attack.

Sans had been walking, the cat idly pawing her way in front, when there had been a scream. Not a good type of scream, either. It was a teenage guys scream, from a nearby alley.

"Uh oh…" Sans took a step back, much like the other civilians did, eyeing the alleyway. Not good. Sans just wanted to wonder around, and there was already an event?

Sure enough, there was. Some big green blob rolled out into the street, holding some poor teenage boy hostage, struggling wildly but unsucessfully escaping. His supposed friends scattered, screaming loudly for a hero as the kid started to spit out fire from his hands in an attempt to free himself. Pretty useless, as if hurt everyone else but the blob.

"It's a super villian!" A nearby person screamed with terror, "Call a hero!"

Another burst of fire spread out. In his panic, Sans shot up his arms, causing a wall of bones to shoot up and protect him and his cat. He ducked down, grabbing the little feline, and jumped back to gain some distance.

This guy wasn't calm in the slightest. Neither of then were. The fire teenager was yelling wildly despite being a hostage, and the blob man was trying to possess the teens powers.

"Ma'am, you need to leave immediately!" A hero had tried to tell Sans, grabbing his arm.

"Don't call me ma'am." He ripped away his arm, immediately pointing to the kid. "Why aren't you guys doing anything?"

"Well, it's a very difficult -"

"It ain't difficult at all! Just fight the guy and save that kid!" Sans held his newly obtained pet closer. "Isn't that your job?"

Undyne would have rushed in and beaten this person to smithereens if given the chance. Yet here this guy was, standing idly by, watching some kid be attacked and not even bother to step in.

“He clearly wants the kid alive because -” Sans paused, rolling back his head with a groan. Sometimes he really hated humans. “Just go help him, not me!”

Maybe Sans should have just taken a nap instead of exploring. This was becoming annoying real quick. He was tired, and didn’t want to deal with this.

Not everyone had that opinion, though.

Before Sans or the guy could even react, some kid sprinted out from the crowd, green hair bouncing, and threw his bookbag towards the blob. The two kids started shouting as he tried to release him, but there wasn’t much luck to be had.

“Son, what are you doing?” The man had had been talking to Sans quickly turned, outstretching a hand in his panic. “You can’t go near that thing!”

The kid wasn’t going to make it. Neither teenager was going to.

He needed to do something.

~~~~~~

Boring tapping echoed around the empty street as Sans walked along, his flip flops clapping in tune with his cats paws.

Okay, admittedly not the… uh, best idea earlier. He had run up and grabbed the two kids, using a bone of sheilds to protect them from the blob, then had grabbed the guys soul and threw him back. It was not worth it in the slightest. Not only had the blonde kid tried to bite Sans (and succeeded, by the way) when he grabbed him, some hero appeared not even a second later to defend all three of them. So not only did Sans barely help, waste his powers, and ended up getting bitten from the guys panic, he also had been sat down and sternly lectured with the green haired kid about running in stupidly. And, apparently since Sans didn’t have a quirk license, whatever that meant, he had been given a fine of sorts for using his magic in public.

Not a great first day. The rest of it was fine, but were villains a regular occurance? If so, that’d make his life adjusting here a little bit more difficult. He really just wanted to laze around, he might not be able to like before.

Sans paused near an alleyway, turning towards the darkness. “Hey, hotshot, I know yer following me,” He said, adjusting the leash in his hands.

“Perceptive,” The person who had been following him took a step out of the shadows, then another.

“Guess so,” Sans mumbled.

They didn’t seem to threatening, but they were following him, so he wanted to keep his guard up. Black hair, weird scarfs, and dark clothing.

“I don’t want to waste time, so I’ll cut straight to it,” He said, fingers cupping his chin. “I saw what you did to the slug.”

Slug? Oh, he thought it was just a blob. Whoops.

“I didn’t do anything to it, though,” Sans said, scratching the side of his head from the embarrassment. Typically he never entered fights, and the one time he decided to ended up not needing him.

“It’s not about what you did or did not do, but it’s about what you can do.” He lazily dragged a hand across his chin, watching Sans with an unreadable expression. “It’s about how you did that. I’ve never seen someone with a quirk who was able to ignore mine.”

Uh… okay? Sans glanced to the side. Did he accidentally make this guy offended or something?

“Sorry if I did anything to offend ya, but -”

“No, I was trying to cancel out your quirk. I had been looking at the young fire boy to try and stop his, but you had gotten in the way. Without your quirk being affected by mine. Which means… whatever you did out there, it wasn’t a quirk at all, was it?” He pointed a finger out towards Sans.

“‘Course not, it was my ma…” Sans trailed off, lips immediately pressing into a line when he remembered there was no such thing as magic here. Shit.

The man narrowed his gaze. Yeah. Sans was in trouble. Whoever this guy was, he wasn’t very pleased at the others lack of response.

“Welp,” Sans said, picking up the cat he now wanted to keep as his own. “It was nice talking to ya, scarfy. Bye!”

“Wait a minute -”

Before he had a chance to stop him, Sans dove around the corner onto the other street, immediately using his magic to rip himself across time and space and land in front of his apartment. Yeah, he’s not dealing with that.

The building itself wasn’t much better than the room that was now his. Tall but shabby, filled with poor people who had to settle just to get by. Mostly quirkless, he had noticed, or people with useless quirks, like one who could twist can bottles whenever he got sad. Whatever society Sans had been dragged into, it wasn’t perfect, that was for sure.

Arriving at the apartment reminded Sans of how bad it was. This girl must have just been laying in bed for days before she finally called it. If Paps ever visited, he’d freak out. Heh. Good times.

He huffed, covering his nose and shaking his head. He had to clean up something, no matter how lazy he was. So, he picked up a bag, and started cleaning.

~~~~~~

Sans only cleaned the necessary. Not the broken window, not the ruined, creaky bed, only the cat feces and the overflowing litterbox. He also made sure to see how much food he had and make a list for more. Ideally, he should be able to snag three jobs and start working off that debt, along with that ‘quirk’ loan, and then get a head start on his new life. Heck, if he could apply to some college tests, his background in science would definitely give him a boost.

The knocking had sounded just before Sans was done with breakfast. Pulling up from the table, he outstretched a hand to pet his cats soft fur as he walked by. He decided to keep the cat in this life, she’s a sweetie and he’s always preferred cats over dogs. Didn’t demand as much attention pet wise. Though the dog monsters were always fun to play poker with.

When he opened the door, Sans almost choked on his breath. Because behind it stood the guy from last night, strained eyes staring at Sans. How did he -

“You shouldn’t have run when I have access to housing info,” He said.

“Oh, so you uh… you can do that, huh?” Sans looked around.

“I’m not here to kill you, don’t look so panicked, I just need to talk,” He said, pulling out a folder with a picture of a woman and a name printed on the front of it. “And don’t disappear again. If you do I’ll consider you a criminal and have you on wanted posters.”

Oh, great. Just _great_. Sans’ eye twitched, usual smile forcing the corners of his lips higher from stress.

“I don’t want to do that, but you ran from me last time, and I need to get a proper understanding of you, especially since I’ve looked at your file,” He said, flipping it open. “Your quirk is registered as a soul passing one, but you displayed a different power altogether yesterday. On top of that, you used a different power on the street last night. Along with your previously mentioned quirk, the sudden changes, and your change in appearance from your drivers license, I could make the guess that you aren’t the same soul that inhabited that body before. Am I wrong?”

Silence fell. Sans stared at him quietly, unable to properly voice any sort of statement. What was this? What was this guy planning?

“Did yer know the girl before? Before she used her quirk?” Sans asked.

“No, I did not. I only decided to try and follow you when my own quirk didn’t work on you, then decided to pull up your files when you disappeared. This all only makes sense with the womans quirk. She had the ability to remove her soul from her body. That would explain why my powers don’t work on you. Because you aren’t using quirks, you’re using something else. And it also explains why your hair and eyes look different.”

This guy was smart. Really smart. When he managed to get the pieces, he connected them together way too fast for Sans’ liking.

“Yeah, okay, I fold.” Sans held up his hands in surrender. “Name’s Sans. I was a skeleton in a different world, but when I was killed I was brought into this one by the girls perk. I can use my magic I had from that world since it’s connected to my soul. And now I’m stuck in this body in a world I’m still not fully used to yet.” Sans gave a soft smile. “You got me. I’m caught. I got magic and shit that no one else here has from what I can tell.”

Sans wasn’t one to tell the truth often, but it didn’t seem like he had much choice right now. And hey, this was a new life.

“It’s quite unlucky for you to get stuck in a body of someone with significant debt,” The man mumbled under his breath, before looking up back at Sans. “I have an offer for you.”

An offer?

“My name’s Shōta Aizawa, I’m known as the pro hero Eraserhead. Your power isn’t affected by mine, which means you could be a large threat, or a big help. I can not only help register you to get rid of your debts, but I’ll teach you about this world. Before you fall into the wrong hands.”

The wrong hands, eh? Sans wasn’t stupid, he knew he was strong and how to handle it well.

“What would I have to do?” Sans asked, carefully gazing at him.

“I need you to be an assistant teacher to myself, in eight months from now,” He said, outstretching a hand. “Do you accept that offer?”

An assistant teacher?


	3. Chapter 1

Birds chirped as pupils peaked out from under a turrent of white hair. They stared deathly at the wooden desk, lightly groaning as Sans dragged himself up from his nap.

He was in the teachers facility room, in his assigned desk besides Aizawa’s. Or, as he called him on a few occasions, Eraser top. The reason behind Sans’ awakening wasn’t natural, no, as a ruler had been lightly smacked against the back of his head.

“The students will be coming in ten minutes,” Aizawa said, laying a brown paper bag next to Sans’ head. “And my wife made you lunch.”

“Heh,” Sans muttered, sitting up in his chair and lightly rubbing his eyes. “Thanks.”

It’s been eight months since he ended up in this world, and quite a lot had happened. Not much significant, if he were to judge. Sans didn’t really fight any villains or get involved in much so far. Aizawa took Sans back to his house to meet his wife (lovely woman, loves to cook, so safe to say Sans was totally willing to stay for the food) while he was registered as a new person. Sans font, with the quirk known as the Skeleton quirk, which gave him the abilities of a skeleton. Aizawa said it’d be best for Sans to pretend his other magic didn’t exist in public, to keep it hidden from villains, which Sans was totally down for.

After Sans was set up, he just learned about this world. About the schools, quirks, expectations, things like that. He wasn’t great at it, but Sans had his own little house, a decent understanding of the world, and was officially Aizawa’s assistant teacher, so that was pretty cool.

Well, that last part wasn’t fully true. He was assistant teacher to the class of 1-A in the school. Class 1-B, the only other class in the hero's program, wouldn’t have an assistant teacher. Bad for them, Sans’ puns were awesome.

Sans was frankly really glad he was being put in with teenagers instead of children. Sure, Sans was good with kids, but he was a more upfront and real kinda guy. And he was better with dealing with angsty teenagers and their drama. No one knew this, but Paps went through one hell of a rebellion phase. Even drew black lines around his eye sockets and wore leather coats. He always made sure to bring that up to make Papyrus’ face go blushing real fast. Good times.

The annoying part about his new life was certainly the stupid fights that broke out on streets. All. The. Time. He was patient, but teleporting in public always caused a panic, forcing him to backtrack and find a less populated spot to shortcut away in. Aizawa once got startled so hard he screamed like a little girl. Sans was _never_ going to let him live that down.

The worst was the separation of good and evil. Sans’ karma abilities didn’t exactly like that. He was always a middle guy, never picking sides, always staying in the background until he had to step in. Being a hero sounded awful. That’s why he was glad just to be some assistant teacher to make sure the kids wouldn’t get themselves killed. That meant he could nap all day and enjoy constant fights, like a movie. Sounded pretty nice. No need to say who was good or evil, but just to sit in the background like he always did.

“She also wanted to ask if you were coming to dinner tonight,” Aizawa said, bored eyes sweeping across Sans’ desk.

Sans and Aizawa had an interesting relationship. Since they were kinda stuck together for three months before Sans got a place to stay, they ended up becoming friends. Aizawa wasn’t as lazy as Sans, but he could come close, so they bonded other that, along with their deep care for family. Then there was Aizawa’s wife, who ruled. She was awesome! Both she and Aizawa liked Sans’ puns, so they would certainly continue to be friends.

“Course. Gotta add some meat to these bones, don’t rib me on!” Sans yawned.

“That wasn’t even an attempt at a good pun. How tired are you?”

“Very.”

“That makes sense.”

“So I just gotta report down there with ya, right?”

“Yes. I’ll be doing special training with them. Did you go over the exercises I prepared?”

Sans nodded. “For a bit last night. Guess they’re going to miss orientation. Which means -” He pumped his fist excitedly. “I don’t have to go to orientation. Score!”

The teacher orientation alone sucked. And Sans was an assistant! How come he had to suffer? The most he had to do was follow around one class and keep them calm. That should be it.

“I’ll meet you there. Make sure to take a shortcut over.”

“On it teach’.”

When Aizawa finally dragged his scarfy face away, Sans leaned back, watching the ceiling with tired eyes. He saw the kids in the entrance exam, they were good. All of them. Undyne would be happy to have those little kids on her guard.

He sighed, and pulled himself out of his chair, hands digging into his hoodie pockets. Sans managed to snag a blue hoodie kind of similar to the one he wore before, but this time with longer black basketball pants. Aizawa had been a real help with a diet for Sans’ body. The poor girl had been on the brink of starvation before he took over, but now the body was better.

Maybe he could scare his students with a shortcut. That’d be fun.

When he finally did arrive, it was to talking from within the classroom. Aizawa had a clear look of annoyance across his face, obviously so done with this class despite it being the first day.

"Oh, hello Sans. You're late."

Sans let loose a shrug, grinning at the students as he stepped inside. "Sorry. Got caught up eating a hamburger. Guess we'll have to ketchup right now."

A few giggles, some groans. Okay. Divided crowd. He recognized them all. Particularly two from his first day.

"Hey chomps, 'member me?" Sans offered a wave to the blondie.

"Chomps?" He screeched, face red and puffy from being angry quite often. Oh, he was not going to be fun to deal with.

"You're that bone lady, from when we fought the slug!" The green haired boy said.

"This is your assistant teacher, Sans. Unlike me, who has you only certain times of the day, she'll be assisting all of your teachers for your class and getting to know you kids. Today she's just sticking with my class since it's her first day."

At first it was a bit weird to be called a girl, but he found he didn't really mind it. If anything, the teaching part was going to be the biggest adjustment. Tori always loved teaching kids, Sans wasn’t exactly great at teaching them things.

"Sup. I'm Sans. Your assistant teacher. Here to be asked questions." He paused for a moment, looking over. "I'd sit down to nap but we're about to be moving."

"Moving?" One of the girls asked, raising a hand.

"We're doing a quirk test." Their homeroom teacher held up a uniform. "Get changed and go outside."

“Won’t we be missing orientation?”

“Yes. I don’t care. Go get changed.”

Sans watched with amusement as the kids almost jumped out of their seats to get changed. Once the room was drained of their manic energy, he turned towards Aizawa, grin steady on his face.

“So?” Sans asked.

“So?” Aizawa hummed in confusion.

“You didn’t like greenie when we first watched him.” Sans leaned against his podem, poking the mans cheek. “I know you’re big on expelling kiddos, but uh… maybe give him a chance?”

“Injuring his entire body everytime he plans to use his power is self destructive, I won’t support that.”

Aizawa sighed, twisting his head back and forth to stretch his neck. Sans knew his neck was one of the guys more important parts. Sure, the eyes were needed for his ability, but if he turned his head too slow, it wouldn’t matter. Aizawa needed to be fast turning his head to stop someone’s quirk.

“Let’s go,” He said, “And while your puns are funny, please don’t say them to the kids too much. This is serious training that can -”

“That can make or break their futures, yeah,” Sans said, “But that doesn’t mean they can’t feel a little happy doing it. We’re training kids, Aizawa, not soldiers. Ain’t that why I’m here? You teach them, I entertain them and keep ‘em happy.”

He sighed, then like a slug, rolled off in his thick, almost suffocating bag. Sans shrugged, still grinning, and ported away.

~~~~~~

A quirk assessment test. That’s what Aizawa had prepared for the kids. Sans had brought out a lawn chair, with a cushion, and was sitting criss crossed upon it as Aizawa explained the basic rules of the surprise test. Every once in awhile, Sans would add in a joke or pun. Aizawa almost snapped at them for a moment about not taking it seriously enough, but Sans quickly butted in to calm him down.

“This just means you guys have to acknowledge that this training is meant to prepare you for real deadly events. It might be a game now, and you guys can have fun, but there are going t’a be consequences if you always think it’ll just be a game. Sure, have fun now, that’s alright, but this ain’t middle school anymore.” Sans shot a look at Aizawa. “Be a little nicer to ‘em, buddy. C’mon.”

Aizawa rolled his eyes. “Sans, sometimes you just… nevermind.”

“I know. I make guys speechless.”

One kid from the class, some boy with red hair, covered his mouth as a snort escaped.

“Bakugou,” Aizawa said, looking at the blonde kid that bit Sans before. “You’re up first.”

“It’s chomps man!” Sans said, perking up. “Hey! How’s the teeth? Still biting people who try to save you?”

The kids face quickly flushed at that reminder. “Hey! I didn’t need your help! I was trying to attack and you got in the way! Both you and Deku!”

“Got in the way of closing yer mouth apparently.” Sans winked at him.

With an annoyed huff, Bakugou glared sharply at Sans, and snatched the ball from out of Aizawa’s hands.

The test pressed on, bringing some students some nervous shivers at the thought of being expelled. Sans managed to talk good old Aizawa out of expelling a student on the first day, though he had a sneaky suspicion that Aizawa was simply going to expel them on the second day. Aizawa was that kinda guy.

Through the quirk test not only did the students get to learn about one another, Sans also got to learn about them. Some of them had some really awesome quirks. Bakugou - Sans was debating to call him chomps or biter, not sure on a nickname yet - had explosive powers. Midoriya, or Deku, didn’t seem to be using his powers, and that was with good reason. Uraraka, some brown haired girl, could float things with only a touch. So far, even though Sans wasn’t supposed to pick favorites, he found her the best. Mostly because she laughed at his jokes.

There was one kid, which Sans already forgot his name, who really seemed to obey authority. He respected the hell out of Sans and Aizawa. And honestly, looking at the two of them, the kid really shouldn’t. Aizawa and Sans were lazy little shits that had to be cared for by Aizawa’s wife. She was a godsend of a person.

Seriously, who makes such good casserole?

“Sensei Sans?”

One of the students, Momo Yaoyorozu, had approached him with a raised arm.

“No need kiddo, just call me Sans,” Sans said, turning towards her. “What’s up?”

Yaoyorozu nodded swiftly. “Sorry. I was just wondering what your hero name was, Sans. Our academy is full of popular heroes as teachers, but I don’t recognize you.”

“That’s easy,” Aizawa stepped into their conversation, arms crossed on his chest. “Sans isn’t a hero.”

“What?” Apparently he had spoken louder than he intended, as over half of the class had turned their heads sharply.

“I’m not a hero or villain. I’m a middle person, I like to stay in the crowd and watch a lot, I just step in if someone’s about to die.” Sans picked at his teeth, feeling rather tired despite having claimed a nap. “I’m not a qualified or registered hero. I was just admitted to the program because Aizawa requested for an assistant teacher, and since he’s your homeroom teacher, that’s why I’m stuck to your class. Nothing really more to it.”

Sans hasn’t really had any opportunity to use much of his magic in this world, so the school couldn’t judge his full extent of his powers. They probably would have eagerly made him a real hero if he did, but Sans wasn’t really that type of heroic figure. That was Papyrus, each and every time.

“I don’t care, we have a hot teacher,” One of the kids with grape like hair muttered, almost dooling to himself.

“Mineta, shut up and throw the ball,” Aizawa said, tossing the object so fast the boy had no chance to catch it, effectively having it slam into his face and cause him to land onto his butt.

And just like that, they were back on track.


	4. Chapter 2

The first day wasn’t so bad. Sans managed to learn all of the kids names, so he’d say he scored pretty well. After that he had went home, gave his cat some tummy rubs, then got in quite a bit of sleep. Then slept in.

Whoops.

Most of the staff was actually pretty chill about Sans sleeping in. He had a month before school even started to get to know them, so they knew pretty well that he was a napper. Sans didn’t even technically have to be in the first half of the day, though he could be called down for homework help. Which had happened today.

“I said I don’t need any help!” Bakugou had snapped when Sans walked into the room, “So go away!”

“Hey, if he said he doesn’t need help, I mean, I could go into the back and take a nap.” Sans pointed over his shoulder.

Yamada, the english teacher, shook his head. “No, you have to help him! We need him to understand this! It’s only the second day and he’s struggling. Oh boy oh boy.”

Sans slowly looked between Yamada and Bakugou, then pointed to himself. “I don’t even fucking speak proper english, how do ya expect me to teach him?”

“I have another class to teach, this is his study hall. Just help him however you can.”

Yamada was a pretty decent guy, Sans had learned that when working with him. They both had set up the kids uniforms earlier, and Yamada didn’t skip on the work. Was pretty chill to Sans as well. However, Bakugou…

“I said I don’t need -”

“Yeah, yeah, yer said that, now shut it.”

Sans plopped himself down into the seat next to the kids, looking down at the assignment. Verbs. Adjectives. Seriously? Sans was good at talking to people, but he didn’t know the fundamentals. Whenever he entered english he might as well had been given an F.

“Oh shit, your assignment sucks,” Sans said, before pulling out his phone. “Yeah we’re going to google this.”

That had caught the kid off guard, because he made a noise as Sans pulled out his phone. “Aren’t you supposed to know this?”

“I’m a scientist, and I know how to talk english, so knowing this kinda stuff was something that never stuck to me. Sorry, guess I’m not real good at my job, heh.” Sans shrugged.

There was a moment of silence between them. Bakugou snarled out a noise, stared down at his paper for a moment, before he swiped it to the side and stood up.

“I didn’t ask for your help, and I certainly don’t need it!” He growled, before stomping off.

What a great first tutoring session. Sans sighed, crossing his arms and staring at the paper as it fluttered down to the floor.

What was with that kid, anyway?

So Sans stood up and left.

The second day was about as simple as the first, though one of the students (obviously Bakugou) decided to go a little overboard. The guy had some serious anger issues, or some pride that was left to overload his brain. Sans watched the kids with interest, but only added puns occasionally. Because honestly, there wasn’t much for him to add teaching wise. Plain and simple, Sans sucked as a teacher.

It was after school, when Sans was looking over the lesson plans, that sans had heard a voice. Granted, it was only the second day, so the students weren’t very fond of him, and vise versa, but there was some very obvious relationships inside of the class. Particularly blondie chomps and green haired broccoli boy.

And man, did he hear some weird stuff.

Sans didn’t know people could be born quirkless. Since he had lived here for only eight months, he didn’t know all of the ins and outs of this society just yet. That was still a work in progress.

“I lost. I never lose, especially to people like you!” Bakugou snapped, shaking his head as if flies were surrounding him. He muttered to himself for a moment, before lifting his head. “I’m going to beat you, I’m going to beat everyone, and then I’ll become the strongest hero! Even surpassing All Might!”

“If you’re going to surpass the highest ranking hero,” Sans said, lazily walking between them, “Yer might wanna control that temper of yours. It’s not going to get you very far.”

There was a moment of silence, just a moment, where Bakugou stared at Sans. And during that moment, Sans realized just how harder than he expected getting close to all of the kids would be. Because some of them weren’t exactly fond of their teachers.

“You’re one to talk, Miss Assistant teacher, you aren’t a real hero.” He spat out, shaking his head. “I haven’t even seen your quirk. Do you have one? Maybe Deku took yours. If you can’t even help me with English then you can’t help me become the best.”

“So, then,” Sans quietly tiled his head to the side, “You really did want help understanding your English, huh?”

A brief flicker behind the kids eyes before he turned, shaking his head, and grumbled as he walked away.

“Sans? Are you alright?”

Crap, Sans forgot Midoriya was there. The kid looked horrified at what Bakugou had told Sans, big green eyes watering like no one’s business.

“It’s fine, kiddo, I just think he has some ego problems,” Sans said, “And… he ain’t exactly wrong. I’m just the assistant teach’.”

“You are just the assistant teacher, but you’re still working at the best hero school and was hand chosen by our homeroom teacher, you do have to admit that’s quite a feat.”

So he was trying to cheer Sans up, eh? What a lad. Out of all of the kids so far, Sans easily had a grasp on him the most. Because…

If he was wearing a red scarf, he’d be rather identical to someone he knew. Clothing and personality wise.

“Not really, I don’t care for accomplishments or anything, kiddo. Ya don’t need to cheer me up. If anything, you should have reported the bullying earlier.” Sans walked up to him and placed a hand on his shoulder. “I’m a person that doesn’t care about status, and while that’s a big thing for everyone else in this world, I’ll never care. I’m a person of connections. That doesn’t mean other people can’t care, you both want to strive towards the top in different ways, and that’s okay. I should’a supported it a little bit more than just sit back like I’ve been doing, though teaching ain’t really my thing, kiddo. I should be able to help with his homework and help with him, but I can’t, so he’s a bit right. And also, yer don’t have to prove anything to anyone. Popularity doesn’t matter. Because, at the end of the day, you know who you are. You have friends and a family, and they trust and support you as well. Don’t feel pressured by anyone else, ‘right?”

It’s been awhile since he’s given a pep talk, but the kid clearly needed it. He looked almost on the verge of crying, lightly sniffing.

“Welp, Midoriya, I gotta broc and roll now,” Sans said, letting go of his shoulders.

Midoriya stared at Sans with a caught off guard expression. “Was… Was that a pun because my hair looks like broccoli?”

“Yup. Couldn’t think of a pun for yer name so I did yer hair. Bye!”

With that, Sans walked off, overing a wave over his shoulder.

And the next time Midoryia said hi to Sans, he offered a bigger smile than usual, and even asked for him to eat lunch with him and his friends.

Guess things were working out in their own way, huh?

~~~~~~

Time had passed since then. Sans mostly napped through that time, with a bit of kitty cuddles in between, along with dinners from his two friends. He managed to get close to a few of the more open going students, which was what teachers needed to do, so Sans was pretty happy.

It… was okay. Just okay. Sans couldn’t say teaching was, or ever would be, his passion. He was a scientist, always loved doing experiments, not to mention jokes were always fun to do. Pranks as well. Can’t say Aizawa enjoyed waking up with bright pink hair. Once he got over his confusion on how Sans and his wife managed to do that, he then started to throw things at them. Sans had teleported out of the room, snorting the whole way.

“Sans, remember how you promised me you would owe me one?”

Sans groaned, pulling his head back up. He had been in a very comfortable position, mind you. Head tilted back, mouth open, his nap had been pretty nice. Though, for All Might, another friend, he cracked open an eye and watched the skinny version of him approach.

“Heya, big guy. Said I would. What’s up?” He pulled himself further, craning his neck to look for the Principal. Nope, he was alone. “So did ya already get scolded for being heroic all morning or does the Principal have yet to find you?”

All Might grimaced at that. “You saw the news, huh?”

“Yuparo. Saw you used all of your time already. Heh. Just watching it made me feel exhausted. But you mentioned a favor?”

It was true that Sans did promise him an ‘I owe you’. Mostly to keep Sans’ powers shut. Sans wasn’t very fond of people knowing he even had strong magic, sort of the same way All Might wanted Sans to keep his own second form shut in. It was a mutual exchange, but when a student asked how some bones appeared, All Might made such a quick fib Sans had to promise him.

“You were asked to stay here and watch over the school because of the attack, right?”

“Well, it wasn’t really an attack, but yeah, I guess,” Sans said, brushing some stray white hair out of his face.

The reporters that broke inside really showed just how popular this school was. What had concerned the staff, though, was the mysterious force that had broken the gate for the school. So, in their little panic, they didn’t want too many teachers to leave, doing a thorough investigation both on the school and around the perimeter. They wanted people that could get around quick, like Sans, to stay behind for the day in case they discovered anyone. Thus, Sans skipping out on the little field trip and staying here, waiting for any call. Though he doubted one would come, if someone really did break into the school they wouldn’t have stayed. The most they’d find would probably be missing files or weapons.

“Because of what I did earlier, I have barely any time left on my hero form for today already, and I was supposed to go with the kids for their training. Aizawa and Thirteen have it handled, but I’d feel bad if I didn’t at least send a cover for me. Since you’re already their assistant teacher, I was hoping you could go in my place.”

Hm. Sans blinked a few times, staring up at the ceiling. Not a bad idea, but the training had already long since started.

“Did ya get permission from the principal?” Sans asked.

“Since I was already planned to go out, that means one person can leave without us losing any hands. The investigation is almost over, anyways,” He said. “Could you go for me?”

“Eh, sure.” With that, Sans pulled himself forward, white teeth steadily grinning. “I’ll port over. Don’t strain yourself, alright?”

After a few more minutes of light discussion and agreements, Sans closed his eyes, leaned back, and let himself be dragged through time and space to the facility where the training was taking place. They should be doing rescue, right? Sans wasn’t real good at that, wasn’t a hero, after all. Saving people from natural disasters was far from his paygrade.

When Sans arrived popped into existence, his teeth gritted closed from shock, suppressing the hello he intended to share at the scene.

This wasn’t good. At all.

**Notes for the Chapter:**

> I am already far into season 3 of the anime, and I've only been watching it while I animate, and I've just finished with the draft of the meme, rip
> 
> also this was the last chapter I had prepared so be ready for random uploads


	5. Chapter 5

Aizawa, the man Sans respected out of the many power houses in this world, was pressed down against the floor, surrounded by many unconscious and beaten up people. On his back sat a man, or some sort of creature, so tall even All Might was considered short in comparison. This guy wasn’t going easy on Aizawa, either, having twisted one arm so far back the bone was obviously broken. His clothes, usually black, were now red from blood.

“Stay back!” He was quick to turn towards Sans, eyes wide. “These are villains!”

“Oh, we have a visitor,” A voice hummed.

The other was a man, in his mid twenties, with light blue hair and several hands pressed against his body. Seeing dead hands stylized like that made Sans take a step back, swallowing thickly. Monsters turned to dust, but humans didn’t. It was always a little gross to see rotting, dismembered parts. Especially on someone’s body.

“The quirkless child seemed to have brought a friend, one that appeared out of nowhere. A teleporter quirk, huh,” He mumbled, starting to scratch at his neck. “Warp gate, you useless piece. If he wasn’t our ticket around I’d tear him limb for limb.”

Two people, and this guy was probably talking about a third. No students around, in the open at least, since Sans could see three people floating in a nearby body of water. Broccoli. Frog girl. Pervert teen. They were staring in horror and shock, and some drool in Mineta’s case.

“Shit,” Sans cursed under his breath, using his magic to feel for the creatures soul. It had one, a weird looking one, but a soul nevertheless. The moment Sans managed to grasp it, he ripped it to the side, effectively slamming it into blue haired handy boy, as Sans called him, and quickly teleported over to Aizawa’s side.

“Holy shit dude, what the hell happened?”

Aizawa was _not_ in good shape. Not only were several of his bones visibly broken, one of his elbows was cracking, almost decaying in a sense.

“They’re here to kill All Might, they… that thing is powerful, stay away from it,” He said, though his voice wavered, dropping in volume. His eyes blinked rapidly, trying to keep himself awake. “You need to grab the students, get out of… here… please…”

Sans gently let him lean against his body as he passed out, head lolling back. That wasn’t good. At all.

“Two quirks, that woman had two quirks,” The handy man growled, starting to scratch at his neck. “Bastard… Father, she has two quirks, she’s fast, I didn’t even see her move…” He dug into his neck further as Sans helped the homeroom teacher onto the floor, setting him down slowly. “We’re losing, we have to withdraw, All Might isn’t coming.”

He seemed to be complaining to himself like a whining child. As he continued to scratch at the side of his neck, he muttered, watching Sans with an intense gaze easily warranted to one of bloodlust.

“So you guys are withdrawing just because I showed up? Man, I feel kinda offended,” Sans said, looking across them. One of them had strength, that seemed to be his quirk. The other remained undetermined. Best to keep a safe distance from strengthy for now. “But hey, I won’t stop ya.”

“Nomu, deal with this person, I want to send All Might a message.”

As the big beast rumbled forward towards Sans, he saw, in a flash of speed, the blue haired man suddenly appear in front of the three students. One of his hands outstretched towards Su’s face, and he could see a terrified expression cross over the three as it got closer.

Clearly this guy had some quirk, then. And something bad.

Sans let his magic rush over him and quickly appeared right between the two, giving him no time before the hand intended for the teenage girl behind him instead lay across his face.

And… nothing happened?

He didn’t feel any pain from the touch, but the guy seemed to grin under his hand. Was his quirk active?

That’s when Sans felt it. Not pain, but something fall onto his shoulder. He took a side glace and found a piece of flesh - his human flesh - on his shoulder.

“Sans, that’s Tomura Shigaraki, his quirk lets him decay anything it touches!” Hands from behind tried to pull him out of the mans grasp, but he held firm.

“Decay, huh?” Sans asked.

He found himself grinning as he placed his own hand on the guys wrist. He could feel the guys fingers. Not only on his flesh, but on his bones. On his jawline. It felt like like it did before when he was a skeleton. And despite the lack of flesh on his left side, the flesh that was now decaying onto his shoulder, he could move his mouth into a smile. After so long, he felt his bones again.

This wasn’t his body. Sans had been taken from his own body, so this flesh wasn’t connected to his soul through H.P. As long as his soul remained intact, and he still had this body to host, he’d be fine. Even if all of the flesh was torn away and they left the skeleton, Sans could still use that skeleton.

And you couldn’t decay bones.

“I guess your quirk doesn’t work then, pal,” Sans said, dragging the mans hand away to properly talk. “My quirks a skeleton quirk. So decaying my skin doesn’t even hurt me.”

Monster bodies were only projections of magic from the soul. As a result, directly attacking those bodies hurt the soul, since they had essentially become a part of the soul. But placing a monster soul into a human body wasn’t going to directly connect them. Sure, his magic altered the girls looks a bit, but it was an organic body for a nonorganic monster, his soul would never truly connect to it. It’d be like placing someone into a mechanical suit. Sure, you could control it, and feel the blows, but it wasn’t your body. Sans had figured out the fleshy part of him wasn’t fully connected when he didn’t realize he had gotten a cut in his first month. Only when he bumped so hard it hurt his bones did he discover the truth behind his body.

“Doesn’t… hurt you?” The man asked, and asked it so quietly it could be considered a whisper, lowering his head to look at his hand.

And during that moment, ever so brief, did silence cross everyone. It was short lived when the creature, Nebu, still followed the previously given orders and slauntered up to Sans, raising an arm to attack.

“Oh shit, here we go kiddos!”

He quickly snatched everyone within the area into his arms and teleported away. Because of this, he ended up with one of the decaying hands pressed firmly against his arm, causing more flesh to start and break away.

“Why did you grab me?” Shigaraki hissed out, dragging his body back.

“Yeah, why d-did you save him?” Mineta asked, finger shakily pointing to the enemy.

“Because I’m not going to let some guy die just because he’s a little pissy,” Sans said, dropping the grape looking teenage boy onto the floor with a huff. Sans knew the kid was going through a girl phase, but ever since he tried to sneak into the girls changing room, Sans wasn’t very tolerant of him. “I could have left you to die, if we’re judging on actions, since you clearly see woman more as eye candy than people during certain times.”

He gulped, looking away. Su ribbeted, giggling at him.

Shigaraki laughed, shakily standing up. “You heroes are all the same…” More scratching. “You pretend to save people but then go around inciting violence. I can’t wait to destroy you all…” He was growling in annoyance like a toddler would, scratching so much blood starting to gather under his fingertips.

“Uh… I’m not a hero,” Sans said, “Just so ya know.”

The three students watched as Sans walked forward, each word accompanied by a step. Honestly, Sans didn’t know what he was doing. Maybe stalling. He could attack this guy. His quirk had no effect.

“I never did say I was one, buddy. I got a skele-ton of things people don’t know about me, but one thing I don’t lie about is my stance. I’m not a hero, I don’t have that stupid lisencse, but I’m not a villain either. I’m a middle person. I don’t like to pick sides, ain’t really my thing. Name’s Sans, Sans the skeleton. I picked ya up because nobody dies on my watch, not unless I want ‘em to. And, quick note,” Sans stopped right in front of him, the revealed eye socket sparking blue with his magic, “You should make sure your enemies don’t get too close to you.”

A grasp of his soul, and Sans was throwing him backwards. A large portal pulled open before he hit the wall, causing him to vanish into wherever the portal led to.

“It’s time to go,” Portal man said quietly, turning around, and disappeared as well.


End file.
